Our previous grant (MH#51583) found that serious degrees of interpersonal conflict within families posed significant problems for the majority of families of ADHD teens, and markedly more so in ADHD teens with co-morbid oppositional - defiant disorder (ODD). Our initial grant also examined the effectiveness of three family-based treatments for these conflicts. At the group level, all treatments produced equal and significant reductions in conflicts with only minor differences among them. At the individual level, however, up to 80% of the families showed no clinical significant or reliable changes due to treatment. Clearly, the potency of psychosocial treatments for families of ADHD/ODD teens requires enhancement. Several factors were identified that could focus such efforts. These are: 10 including fathers in therapy with the adolescent; 2) increasing the number of therapy sessions; 3) combining promising therapy approaches; and 4) evaluating the separate role played by fathers in family conflicts. We therefore propose a 3 year renewal of our grant to conduct an additional study of parent-teen conflict and its treatment in ADHD/ODD teens. The study will involve 90 teens with ADHD and ODD randomly assigned to either problem-solving communication training (PSCT) alone or to PSCT combined with parent behavior management training (BMT). All subjects will receive 18 sessions of therapy but will be re-evaluated half-way through therapy to evaluate treatment effects as a function of dose of treatment (9 vs 18 sessions). Father involvement in therapy will be strongly and systematically encouraged. The therapies, therefore, will be enhanced by addressing all of the above noted factors (dosage, treatment combination, father involvement). Rating scales, therapist ratings, and direct observations of mother-teen and father-teen interactions will be used to assess treatment process and outcome effects. Potential predictors of treatment outcome will again be examined.